1. Field of the Invention
The present invention relates to a medical manipulator system including a working unit which is operable on the basis of an operation command input from an operating unit.
2. Description of the Related Art
In laparoscopic surgery, a number of small holes are opened in a patient's abdomen or the like, and an endoscope, a forceps (or manipulator) or the like is inserted, and surgery is carried out while the surgeon observes an image from the endoscope on a monitor. In this type of laparoscopic surgery, owing to the fact that opening of the abdominal cavity is unnecessary, the burden on the patient is small, and the number of days required for the post-operative recovery and the number of days spent in the hospital can be significantly reduced. Therefore, laparoscopic surgical operations are expected to find an increased range of applications.
As disclosed in JP 2004-105451 A, for example, a manipulator system comprises a manipulator and a controller for controlling the manipulator. The manipulator comprises an operating unit which is manually operable and a working unit replaceably mounted on the operating unit.
The working unit (instrument) comprises a long joint shaft and a distal-end working unit (also referred to as an end effector) mounted on the distal end of the joint shaft. The operating unit has actuators (motors) for actuating the working unit at the distal end through wires. The wires are wound around respective pulleys disposed in a proximal end portion of the working unit. The controller energizes the motors of the operating unit to cause the pulleys to move the wires back and forth.
The working unit does not include electronic devices such as sensors or the like because it should easily be cleaned and sterilized, and is incapable of directly detecting the positions or origins of the pulleys disposed in the distal-end working unit and the rear end of the working unit. The axis positions of the distal-end working unit are calculated based on respective angular displacements of the motors.
Various different working units, including a gripper, scissors, an electrosurgical knife, an ultrasonic knife, a medical drill, etc., are used to perform respective surgical techniques in a laparoscopic surgical operation process. These working units are detachably mounted on the operating unit. When the working units are selectively mounted on the operating unit, the pulleys in the proximal end of the working unit are held in engagement with the rotational shafts of the motors in the operating unit.
In a system where different working units are selectively connected to one operating unit, it is necessary to establish a motor phase which serves as a common axis position for allowing all the working units to be detachably mounted on the operating unit (see, for example, JP 2004-105451 A). The established motor phase is referred to as an origin or initial position.
If the distal-end working unit is to be replaced with another distal-end working unit, then the manipulator itself may be replaced. In this case, the connector of the manipulator which connects the operating unit to the controller is disconnected from the controller, and the connector of the other manipulator is connected to the controller.
In general industrial manipulator systems, the manipulator and the controller keep connected to each other while in operation. However, medical manipulator systems should preferably have the manipulator easily separable from the controller because different types of working units are selectively used, as described above.
Manipulator systems of the related art are disclosed in JP 2004-105451 A, JP 2004-208922 A, and U.S. Pat. No. 6,331,181.
According to JP 2004-105451 A, there have been proposed arrangements which make it unnecessary to take into account motor coil excitation switchover upon installation and removal of the working unit and also electric configurations.
JP 2004-208922 A discloses electric installation and removal of a plurality of distal-end tools (working units).
U.S. Pat. No. 6,331,181 discloses a medical manipulator system including a circuit for acquiring ID, on a manipulator on the distal end. A controller acquires the ID information and controls installation and removal of the manipulator based on the acquired ID information.
As described above, the axis position of the distal-end working unit is calculated on the basis of the origin. If the working unit is to be replaced with another working unit during a surgical process, then the other working unit to be newly mounted on the operating unit needs to be in an axis position that is exactly held in alignment with the origin. Stated otherwise, when the working unit is removed from the operating unit, the working unit should preferably be in an axis position aligned with the origin.
If the working unit is removed while the motors are being angularly displaced from the origin for some reasons, then it may be necessary for the operator to perform a resetting process to forcibly return the motors to the origin. However, since the resetting process is a forcible process that is not performed normally, it should not be activated carelessly.